TK11850LTL TOKO [TOKO, Inc], TK11850LTL Datasheet - Page 10

• Manufacturer Part Number: TK11850LTL
• Description: WHITE LED DRIVER
• Manufacturer: TOKO [TOKO, Inc]

The following are 3 kinds of dimming methods.
1. Dimming by R
The current of the LED (I
Example of 3 LEDs with a 4 brightness level circuit:
TK11850L
GND
V IN
Page 10
C IN
L
R SC
D
C OUT
V OUT
EXT
V IN
I S
0.1 V
LED
R
+
-
I S COMP
L
1
5
E
2
2
3
5
D
0
1
4
7
6
LED
1
0
(9)
0
I
LED
) is determined by R
CLK
vs. R
Q
LED
I
L
S
R
E
V LED
D
2
1
1
1
Cx
CLK
0.86 V
5
1
1
9
4
0
(
4 .
1 .
0.3 V
m
9 .
5 .
6 .
4 .
A
OSC
)
BAND GAP REFERENCE
I LED
LED
CLK
0.525 V
,which can be set by switches such as transistors.
V REF
DIMMING
ERROR
COMP
+
-
R LED1
7
8
EN
GND
V FB
C X
ON/OFF
SW1
C X
12
20
18
16
14
10
4
0
8
2
6
R LED2
CONTROL
SIGNAL 1
10
SW2
R LED3
CONTROL
SIGNAL 2
TOTAL RESISTANCE (R LED )
LED CURRENT (I LED ) vs.
I
R
V
V
LED
REF
FB
LED
R LED ( )
Voltage = 0.525 V (typ)
=
: Total value of Resistors
= 0.525 V (typ)
V
R
100
REF
LED
May 2001 TOKO, Inc.
1000